Method and device for dispersing submunitions

ABSTRACT

The present invention relates to a method and a device for combating a pre-determined target with submunitions directed at the target from an airborne carrier in the form of a rocket, missile or equivalent ( 1 ) whereby the submunitions ( 17 ) are of the type whose main effect in target derives from impact with the target. As claimed in the present invention the submunitions ( 17 ) are given both a lateral motion vector ( 34 ) relative to the direction of flight of the carrier and a motion vector ( 35 ) in the direction of flight of the carrier. Jointly these motion vectors give the submunitions a resultant motion vector in a direction ( 36 ) towards the target. When the present invention is used the submunitions ( 17 ) are given the actual combined motion by the rotating magazine ( 5 ) in which they are stowed that rotates up to a high rate around the direction of flight of the carrier ( 1 ) before the submunitions leave the carrier when the centrifugal force gives them their lateral motion vector and they acquire their longitudinal motion vector from the direction of flight of the carrier.

The present invention relates to a method and device for precisionengagement of hostile targets by dispersing towards the target, from aflying non-rotating or slowly rotating carrier in the form of a rocket,missile or equivalent, a large quantity of submunitions that act bydirect impact in the target via a combination of mass, inherent hardnessand velocity. The submunitions in themselves can be of an elective typesuch as a cube, ball or dart.

Combating a target with fragments is currently the most common way ofenhancing kill probability against targets that are difficult to combatby a direct hit because they have, for example, an extended surface orconsist of numerous small units dispersed over a specific area. The mostcommon method of achieving fragment dispersion must thereby beconsidered to be by using a detonating explosive charge to give thefragments their desired velocity and direction. The fragments inquestion can thereby be either pre-shaped before the explosive chargethat is to disperse them is detonated, or can be formed during theactual detonation such as by bursting a fragmentation casing. Onedisadvantage of using a detonating charge to disperse large quantitiesof fragments is that the limits for true dispersion of fragments are,despite everything, relatively approximate and difficult to predict.This may apply especially when the fragments are formed by fragmenting afragmentation casing since the fragments are then of many differentsizes and thus fly different distances.

As already indicated the present invention relates to a method anddevice for attacking a pre-determined target with a well-defined clusterof submunitions which, just like fragments, act on impact and which aredeployed from a specific carrier in the form of a rocket, missile orequivalent. The method and device as claimed in the present inventionenable dispersion of, submunitions to be actuated with the shortestpossible period of notice, while also enabling the dispersion patternimparted to the fragments to be varied within certain constraints. Asdispersion of the submunitions is intended to operate from the side of acarrier with a relatively high velocity the dispersed submunitions asclaimed in the present invention will be given a forwards and lateralvelocity vector relative to the carrier, which means that thesubmunitions from the carrier can be dispersed obliquely forwardsrelative to its own direction of flight. Dispersion of the submunitionscan then be carried out either simultaneously all around the carrier orwithin a restricted angular zone relative to the cross-section of thecarrier. The present invention also enables variation of the anglebetween the direction of flight of the carrier and the central axis ofthe cluster of submunitions emitted from the carrier. With regard to thesubmunitions we consider that special advantages are achievable if theyare made dart-shaped, since dart-shaped submunitions as claimed in themethod that is characteristic of the present invention can be given astable flight and thereby a greater range and better penetration in thetarget. The method and device as claimed in the present invention fordispersing submunitions enables an evenly distributed dispersionpattern, which is ideal from the point of view of achieving a targetkill.

The basic principle for the present invention is that a large number ofthe submunitions shall be maintained in a state of readiness in thecarrier in a dedicated magazine comprising a number of concentricsubmunitions arranged in ring- or spiral-shaped layers whereby thesubmunitions in the magazine, if they have an elongated form like a dartfor example, shall be located with their own longitudinal axis parallelwith the direction of flight of the carrier. This magazine is rotatablyjournalled around a central axis that is preferably coincident with thelongitudinal axis of the carrier, around which axis the magazine canthen rotate up to a pre-determined rate while the submunitions areretained in the magazine. When the carrier approaches a target to beengaged the magazine rotates to a rate that provides the centrifugalforce necessary to give the desired dispersion pattern in relation tothe distance to the target. The magazine subsequently opens when thecarrier has reached its intended engagement distance, whereby thesubmunitions in the magazine are released and dispersed along thedirectional vectors specified by the resultant of the centrifugal forcein each direction and of the velocity of the carrier in its direction offlight Dispersion of the submunitions is then dependent on where theyare located in the magazine since the submunitions located furthest fromthe centre of rotation of the magazine are propelled by the greatestcentrifugal force thus being given the highest velocity vector lateralto the direction of flight of the carrier, while those nearest thecentre of rotation are propelled by the lowest centrifugal force in thesame direction, and the velocity vector imparted by the carrier in itsown direction of flight is the same for all the submunitions.

By subdividing the magazine into a number of compartments, eachpreferably with a segmented circular cross-section format, the contentof each such compartment can be released individually when the desiredrotational position is attained, i.e. when it is directed at the target,thereby enabling a number of closely consecutive clusters ofsubmunitions to be propelled towards the target during a very brief timeinterval. Each such compartment is thereby provided with its ownperipheral outer wall segment, releasable on command, for retaining thesubmunitions until the correct stand-off distance to the target isreached.

Naturally, all the submunitions in the magazine can also be releasedsimultaneously instead, in which case all the submunitions are dispersedall around the carrier.

As already indicated the device as claimed in the present invention isdesigned to be incorporated in a carrier in the form of a rocket,missile or equivalent, and such projectiles should preferably have asmooth outer casing to provide the least possible drag. Beforedispersion of the submunitions can begin this outer casing must beeliminated and, as claimed in one version of the present invention, thisis achieved by the carrier separating into two parts level with themagazine, each such part continuing along mainly the same stable flightpath but with a somewhat different velocity and with a graduallyincreasing distance between them whereby the part that does notincorporate the submunition-dispersing magazine takes with it the partsof the carrier's outer walls that until the point of separationsurrounded the magazine. The actual separation can be actuated by asmall explosive charge.

The method and device as claimed in the present invention gives thesubmunitions an evenly distributed dispersion pattern, which is idealfrom the point of view of achieving a target kill. It also enables verygood capability for precision engagement of difficult targets, such astargets that one needs to engage while leaving their surroundings as faras possible undamaged. One advantage with the present invention isnamely that one can specify very precisely in advance what thedispersion of the submunitions will be like, allied to the fact thatunder the same circumstances such dispersion will be very similarbetween different carrier units of the same type.

Because the device as claimed in the present invention also requiresvery little space it can be used as a complementary warhead in missilesthat are already equipped with a major warhead, and thereby theproximity fuze of the main warhead and other sub-functions can alsoserve this complementary warhead. To be able to provide the desiredresult the device as claimed in the present invention usually needsaccess to information regarding distance and direction to the target aswell as the relative velocity of the target, and such information shouldbe obtainable from a proximity fuze or equivalent.

In a specially preferred design of the present invention a gas generatorwith a number of outlets arranged tangentially around its own peripheryis used to accelerate the magazine to the desired rate of rotation,after which the submunitions are released via, for example, eliminationof an outer retaining wall that keeps the submunitions in place untilrelease.

The present invention is defined in more detail in the subsequent patentclaims, and is now described in more detail with reference to theappended figures that illustrate one of several conceivable designs of adevice designed in accordance with the present invention.

If required, each carrier unit can be equipped with more of thesubmunition magazines that are a characteristic feature of the presentinvention and if, when actuated, they are made to rotate in differentdirections the gyro effect that otherwise acts on the carrier can beeliminated.

In the appended figures

FIG. 1 shows a partially sectioned missile incorporating the device thatis a characteristic feature of the present invention,

FIG. 2 shows a section along line II—II in FIG. 1,

FIG. 3 shows a lateral section of the device as claimed in the presentinvention to a larger scale and in more detail,

FIG. 4 shows the section designated IV—IV in FIG. 3, and

FIG. 5 shows the section designated V—V in FIG. 3.

The corresponding parts in the various figures have the same referencenumber irrespective of scale and degree of detail.

The missile illustrated in FIG. 1 has two arrays of aft fins 2 a and 2 bthat each comprise four fins, four front control surfaces 3, and onesubmunition magazine 4 that is a characteristic feature of the presentinvention. The latter comprises in general terms a magazine section 5and a propellant motor or gas generator section 6. The magazine 4 isjournalled to be freely rotatable around a central axis that iscoincident with the longitudinal axis of the missile.

These journals are designated 8. The front section 9 of the missile 1contains its control system, possible target seeker and proximity fuze,as well as its main warhead and flight motor. The aft section 10 of themissile 1 contains the submunition magazine 4 and space to accommodatethe missile's launch motor.

The submunition magazine 4 is shown in more detail with its constituentparts in FIGS. 3-5. FIG. 3 shows a section through parts 5 and 6. Thisincludes parts of the outer casing 11 of the missile 1. As shown in theFigure the magazine section 5 and the gas generator section 6 are joinedto each other and are journalled via ball bearings 12 and 13 to befreely rotatable around axis 7. Magazine section 5 comprises two mainlycircular sidewalls 14 and 15, and between them a peripheral outer wall16 forms space for a magazine which, as shown in FIGS. 3 and 5 is filledwith dart-shaped submunitions 17 arranged in concentric circular layerswith their own longitudinal axes parallel to axis 7. The magazine spacebetween sidewalls 14 and 15 and the peripheral wall 16 is divided byfour separating walls 18-21 into four quadrants or compartments K1-K4.The gas generator section 6 comprises a propellant charge 22, twoinitiation charges 23 and 24, a gas expansion chamber 25, and fourtangentially arranged gas outlets 26-29. FIG. 3 also shows fourexplosive bolts 30-33 (in reality there are six explosive bolts in thedevice). The task of these explosive bolts is to remove, at a givencommand at the right point in time, that section of the peripheral wall16 facing the target at the time for engagement. The peripheral wall 16consists, namely, of a number of wall elements, each of which can beremoved individually without the others being affected.

The device functions as described below. The proximity fuze, or otherinformation source such as a remote command, provides data regardingdistance and direction to the target relative to the flight path of thecarrier (in FIG. 1 the direction to the target is indicated by the arrowM). When an engagement has been decided and is imminent the initiationcharges 23 and 24 are ignited whereby propellant gases are generatedthat flow out through gas outlets 26-29 to accelerate sections 5-6 overa very brief interval to the rate of rotation calculated to give thedesired dispersion of the dart-shaped submunitions 17. Simultaneously,or immediately preceding this, the carrier is separated along sectionline d—d shown in FIG. 1, whereby the parts of the outer casingsurrounding the submunition magazine 4 and the explosive bolts 30-33accompany the front section 9 of the carrier while the above mentionedcomponents remain in the aft section 10 of the carrier where they arenow exposed laterally. Thanks to their respective arrays of fins bothcarrier sections 9 and 10 continue along their original flight pathafter separation, but with a gradually increasing distance between them.The actual separation can be actuated by a pyrotechnic charge. When thecarrier (missile) has reached the point in its flight path wheresubmunitions 17 shall be fired, that part of the peripheral wall 16 ofmagazine section 5 that is facing the target at precisely that point intime is removed by the explosive bolts 30-33 to provide optimallydirected dispersion of submunitions.

As illustrated in FIG. 1, when the dart-shaped submunitions leave themagazine they acquire from the centrifugal force a motion vector 34directed radially outwards which, as previously mentioned, varies forthe submunitions depending on their location in the magazine, togetherwith a motion vector 35 acquired from the direction of flight of themissile. All in all these two motion vectors give the motion resultant36. Furthermore, the submunitions acquire dispersion around this maindirection as determined by their original locations in the magazine. Theangle of dispersion is designated a. As the magazine comprises, forexample, four quadrants K1-K4 containing dart-shaped submunitions, eachcompartment can be fired in sequence in the same direction as soon aseach quadrant reaches the position when it is facing the target. At thesame time as the submunitions 17 acquire a longitudinal dispersion asillustrated in FIG. 1 they also acquire a certain lateral dispersion,and as they are fired in the indicated manner—each magazine quadrant insequence—the lateral dispersion is calculated to be the same for allquadrants, and in this case this dispersion is equivalent to angle β.

1. A method of firing submunitions, comprising: providing an airbornecarrier having a magazine rotatably mounted with respect to a frontsection of a missile, the magazine housing a plurality of submunitions;activating a gas generator, wherein gases from the gas generator causethe magazine to rotate; rotating the magazine relative to the frontsection of the airborne carrier to exert centrifugal forces on thesubmunitions; and allowing the submunitions to leave the magazine. 2.The method of claim 1, wherein the gas generator comprises a pluralityof peripheral openings, the openings being disposed to direct the gasesfrom the gas generator to rotate the magazine.
 3. The method of claim 1,comprising: separating the front section of the airborne carrier from anaft section of the carrier, wherein the magazine remains in the aftsection.
 4. The method of claim 3, wherein the submunitions leave themagazine due to the centrifugal forces on the submunitions.
 5. Themethod of claim 4, wherein the gas generator comprises a plurality ofperipheral openings, the openings being disposed to direct the gasesfrom the gas generator to rotate the magazine.
 6. The method of claim 5,comprising: removing at least a part of a peripheral wall from aperiphery of the magazine after separation of the front section from theaft section.
 7. The method of claim 6, wherein the submunition areprovided a lateral motion vector away from the airborne carrier by thecentrifugal forces.
 8. The method of claim 1, wherein the gas generatoris activated when an engagement has been decided, the gas generatorcausing the magazine to rotate up to a desired speed.
 9. The method ofclaim 1, comprising: separating a front section of the carrier from anaft section of the carrier, wherein the magazine remains in the aftsection; and removing at least a part of a peripheral wall from aperiphery of the magazine after separation of the front section from theaft section.
 10. The method of claim 1, comprising: removing at least apart of the peripheral wall surrounding the magazine based on a locationof a target.
 11. The method of claim 10, wherein parts of the peripheralwall are removed as sectors of submunitions surrounded by acorresponding part of the peripheral wall coincide with a direction tothe target.
 12. An airborne carrier, comprising: a front section; an aftsection; a gas generator disposed to emit gases to cause a magazine torotate; and the magazine rotatably mounted with respect to a frontsection of a missile, the magazine housing a plurality of submunitions.13. The airborne carrier of claim 12, wherein the gas generatorcomprises a plurality of peripheral openings, the openings beingdisposed to direct the gases from the gas generator to rotate themagazine.
 14. The airborne carrier of claim 12, comprising: means forseparating a front section of the carrier from an aft section of thecarrier, wherein the magazine is fixedly mounted in the aft section. 15.The airborne carrier of claim 14, wherein the submunitions areconcentrically arranged in the magazine.
 16. The airborne carrier ofclaim 14, wherein the magazine includes separating walls that divide thesubmunitions into compartments.
 17. The airborne carrier of claim 12,wherein the gas generator is a disc-shaped gas generator having an axisthat is coincident with an axis of rotation of the magazine.
 18. Theairborne carrier of claim 12, wherein the magazine and gas generator aremounted on ball bearings on an axis.
 19. The airborne carrier of claim12, wherein the magazine is mounted on at least one journal.
 20. Theairborne carrier of claim 19, wherein the submunitions areconcentrically arranged in the magazine, and wherein the magazineincludes separating walls that divide the submunitions intocompartments.
 21. The airborne carrier of claim 12, comprising: aperipheral wall surrounding the magazine.
 22. The airborne carrier ofclaim 21, wherein the peripheral wall comprises a plurality of removablewall elements, and wherein the submunitions are divided into a pluralityof sectors.
 23. The airborne carrier of claim 22, comprising means forremoving individual removable wall elements as a sector of submunitionssurrounded by that part of the peripheral wall element coincides with adirection to the target.
 24. The airborne carrier of claim 12,comprising: a plurality of fins disposed on an exterior of the airbornecarrier.